The present application claims priority to Japanese Patent Application No. 2001-189909, filed Jun. 22, 2001 and Japanese Patent Application No. 2002-65549, filed Mar. 11, 2002. The contents of these applications are incorporated herein by reference in their entirety.
1. Field of the Invention
The present invention relates to an arrayed waveguide grating optical multiplexer/demultiplexer and a method for manufacturing the same.
2. Discussion of the Background
Recently, in optical communications, research and development of the optical wavelength division multiplexing transmission has been conducted actively for the way to dramatically increase the transmission capacity thereof, and practical applications have been proceeding. The optical wavelength division multiplexing transmission is that a plurality of lights having wavelengths different from each other are multiplexed and are transmitted, for example. Such optical wavelength division multiplexing transmission systems need optical multiplexers/demultiplexers for multiplexing lights having wavelengths different from each other or demultiplexing a light to lights having wavelengths different from each other. As one example of such optical multiplexer/demultiplexers, an arrayed waveguide grating (AWG) is known.
For the high quality optical wavelength division multiplexing transmission, it is required that crosstalk with other channels is small.
According to one aspect of the present invention, an arrayed waveguide grating optical multiplexer/demultiplexer includes at least one first optical waveguide, a first slab waveguide, an arrayed waveguide connected to the at least one first optical waveguide via the first slab waveguide, a second slab waveguide, and a plurality of second optical waveguides connected to the arrayed waveguide via the second slab waveguide. The arrayed waveguide includes a plurality of channel waveguides each of which has a different length and which includes a shortest channel waveguide having a shortest length. Each of the plurality of channel waveguides includes first and second connection portions and a curved portion provided between the first and second connection portions. The first connection portion is connected to the first slab waveguide. The second connection portion is connected to the second slab waveguide. The shortest channel waveguide has a radius (R1) of curvature of the curved portion and an angle (xcex81) which is a half of a central angle of the curved portion. The radius (R1) of curvature and the angle (xcex81) are determined such that a product (R1xc3x97xcex81) of the radius (R1) of curvature and the angle (xcex81) is a value within a range which includes a minimum value of the product (R1xc3x97xcex81) and in which all of the plurality of channel waveguides are drawn.
According to another aspect of the present invention, an arrayed waveguide grating optical multiplexer/demultiplexer includes at least one first optical waveguide, a first slab waveguide, an arrayed waveguide connected to the at least one first optical waveguide via the first slab waveguide, a second slab waveguide, and a plurality of second optical waveguides connected to the arrayed waveguide via the second slab waveguide. The arrayed waveguide includes a plurality of channel waveguides each of which has a different length and which includes a shortest channel waveguide having a shortest length. Each of the plurality of channel waveguides includes first and second connection portions and a curved portion provided between the first and second connection portions. The first connection portion is connected to the first slab waveguide. The second connection portion is connected to the second slab waveguide. The curved portion includes a first curved section connected to the first connection portion and a second curved section connected to the second connection portion. The shortest channel waveguide has a first radius (R1L) of curvature of the first curved section, a second radius (R1R) of curvature of the second curved section, a first angle (xcex81L) which is a central angle of the first curved section, and a second angle (xcex81R) which is a central angle of the second curved section. The first radius (R1L) of curvature, the second radius (R1R) of curvature, the first angle (xcex81L) and the second angle (xcex81R) are determined such that a first product (R1Lxc3x97xcex81L) of the first radius (R1L) of curvature and the first angle (xcex81L) is a value within a first range which includes a minimum value of the first product (R1Lxc3x97xcex81L) and in which all of the plurality of channel waveguides are drawn and a second product (R1Rxc3x97xcex81R) of the second radius (R1R) of curvature and the second angle (xcex81R) is a value within a second range which includes a minimum value of the second product (R1Rxc3x97xcex81R) and in which all of the plurality of channel waveguides are drawn.
According to yet another aspect of the present invention, an arrayed waveguide grating optical multiplexer/demultiplexer includes at least one first optical waveguide, a first slab waveguide, an arrayed waveguide connected to the at least one first optical waveguide via the first slab waveguide, a second slab waveguide, and a plurality of second optical waveguides connected to the arrayed waveguide via the second slab waveguide. The arrayed waveguide includes a plurality of channel waveguides each having different length. A length of each of the plurality of channel waveguides is determined as short as possible to suppress phase errors of lights propagating through the plurality of channel waveguides.
According to further aspect of the present invention, a method for manufacturing an arrayed waveguide grating optical multiplexer/demultiplexer includes providing an arrayed waveguide which includes a plurality of channel waveguides each of which has a different length and which include a shortest channel waveguide having a shortest length. Each of the plurality of channel waveguides includes first and second connection portions and a curved portion provided between the first and second connection portions. The shortest channel waveguide has a radius (R1) of curvature of the curved portion and an angle (xcex81) which is a half of a central angle of the curved portion. The first connection portion is connected to a first slab waveguide. The second connection portion is connected to a second slab waveguide. The radius (R1) of curvature and the angle (xcex81) are determined such that a product (R1xc3x97xcex81) of the radius (R1) of curvature and the angle (xcex81) is a value within a range which includes a minimum value of the product (R1xc3x97xcex81) and in which all of the plurality of channel waveguides are drawn.
According to yet further aspect of the present invention, a method for manufacturing an arrayed waveguide grating optical multiplexer/demultiplexer includes providing an arrayed waveguide which includes a plurality of channel waveguides each of which has a different length and which include a shortest channel waveguide having a shortest length. Each of the plurality of channel waveguides including first and second connection portions and a curved portion provided between the first and second connection portions. The curved portion includes a first curved section connected to the first connection portion and a second curved section connected to the second connection portion. The shortest channel waveguide has a first radius (R1L) of curvature of the first curved section, a second radius (R1R) of curvature of the second curved section, a first angle (xcex81L) which is a central angle of the first curved section, and a second angle (xcex81R) which is a central angle of the second curved section. The first connection portion is connected to a first slab waveguide. The second connection portion is connected to a second slab waveguide. The first radius (R1L) of curvature, the second radius (R1R) of curvature, the first angle (xcex81L) and the second angle (xcex81R) are determined such that a first product (R1Lxc3x97xcex81L) of the first radius (R1L) of curvature and the first angle (xcex81L) is a value within a first range which includes a minimum value of the first product (R1Lxc3x97xcex81L) and in which all of the plurality of channel waveguides are drawn and a second product (R1Rxc3x97xcex81R) of the second radius (R1R) of curvature and the second angle (xcex81R) is a value within a second range which includes a minimum value of the second product (R1Rxc3x97xcex81R) and in which all of the plurality of channel waveguides are drawn.
According to further aspect of the present invention, a method for manufacturing an arrayed waveguide grating optical multiplexer/demultiplexer includes providing an arrayed waveguide which includes a plurality of channel waveguides each having different length. At least one first optical waveguide and the arrayed waveguide are connected via a first slab waveguide. A plurality of second optical waveguides and the arrayed waveguide are connected via a second slab waveguide. A length of each of the plurality of channel waveguides is determined as short as possible to suppress phase errors of lights propagating through the plurality of channel waveguides.